Hydrochloric acid acetylene, reaction with

Vinyl chloride is a gas produced by reacting ethylene or acetylene with hydrochloric acid. The reaction replaces one hydrogen atom in ethylene with a chlorine atom which makes it non-burning. Polymerization produces polyvinyl chloride. Polyvinyl chloride is a linear chain polymer with bulky chlorine side groups. It is conveniently represented as below ... 

Hydrochloric acid may conveniently be prepared by combustion of hydrogen with chlorine. In a typical process dry hydrogen chloride is passed into a vapour blender to be mixed with an equimolar proportion of dry acetylene. The presence of chlorine may cause an explosion and thus a device is used to detect any sudden rise in temperature. In such circumstances the hydrogen chloride is automatically diverted to the atmosphere. The mixture of gases is then led to a multi-tubular reactor, each tube of which is packed with a mercuric chloride catalyst on an activated carbon support. The reaction is initiated by heat but once it has started cooling has to be applied to control the highly exothermic reaction at about 90-100°C. In addition to the main reaction the side reactions shown in Figure 12.6 may occur. 

Polychloroprene rubber (CR) is the most popular and versatile of the elastomers used in adhesives. In the early 1920s, Dr. Nieuwland of the University of Notre Dame synthesized divinyl acetylene from acetylene using copper(l) chloride as catalyst. A few years later, Du Pont scientists joined Dr. Nieuwland s research and prepared monovinyl acetylene, from which, by controlled reaction with hydrochloric acid, the chloroprene monomer (2-chloro-l, 3-butadiene) was obtained. Upon polymerization of chloroprene a rubber-like polymer was obtained. In 1932 it was commercialized under the tradename DuPrene which was changed to Neoprene by DuPont de Nemours in 1936. 

Vinyl chloride monomer (VCM) was originally produced by the reaction of hydrochloric acid and acetylene in the presence of HgC catalyst. The reaction is straightforward and proceeds with high conversion (96% on acetylene) ... 

Hydrochloric acid is thought to give dangerous reactions with metal carbides. There are no further details regarding risks. The dangers may be linked to the acetylene produced. 

The original rnanufacturing route to vinyl chloride (VC) didn t involve ethylene dichloride (EDC) but was the reaction of acetylene with hydrochloric acid. This process was commercialized in the 1940s, but like most acetylene-based chemistry in the United States, it gave way to ethylene in the 1950s and 1960s. The highly reactive acetylene molecule was more sensitive, hazardous,... 

For a decade or so [CoH(CN)5] was another acclaimed catalyst for the selective hydrogenation of dienes to monoenes [2] and due to the exclusive solubility of this cobalt complex in water the studies were made either in biphasic systems or in homogeneous aqueous solutions using water soluble substrates, such as salts of sorbic add (2,4-hexadienoic acid). In the late nineteen-sixties olefin-metal and alkyl-metal complexes were observed in hydrogenation and hydration reactions of olefins and acetylenes with simple Rii(III)- and Ru(II)-chloride salts in aqueous hydrochloric acid [3,4]. No significance, however, was attributed to the water-solubility of these catalysts, and a new impetus had to come to trigger research specifically into water soluble organometallic catalysts. 

A solution of 2.5 mol of sodium acetylidc in liquid NHj (p. 17-19) is cooled to —40 C and a vigorous stream of acetylene is introduced for 2 min (31/mjn). The alkyl bromide (2.0 mol) is then added dropwise over 1 h while maintaining the temperature as close as possible to -38 C Stirring at this temperature is continued for another 1.5 h (for the type of stirrer see fig 3), then 300 ml of high-boiling petroleum ether (b.p. >170 C) is added. The mixture is cautiously poured onto 2 kg of finely crushed ice in a 5-1 wide-necked round-bottomed (fig. 13) or conical flask. The reaction flask is rinsed with a small amount of ice water which is added to the bulk. After separation of the layers, three extractions with small amounts of petroleum ether are carried out The extracts are washed with dilute hydrochloric acid and subsequently dried over MgS04. Isolation is carried out as described in exps. 1 and 3, and in Chap. 1-2.6. The product is carefully redistilled through a 40-cm Widmer column. 1-Pentyne, b.p. 

The substance is stable at ordinary temperatures and up to 100°C. Like cupric acetylide it decomposes on being heated in hydrochloric acid (Berthelot [102], Sabaneyev [107]). A solution of potassium cyanide also causes decomposition with the loss of acetylene. Makowka [108] showed that aldehyde-like compounds are formed from cuprous acetylide on reaction with a 30% solution of hydrogen peroxide. 

POLYVINYL CHLORIDE (PVC). [CAS 9002-86-2], The manufacture of polyvinyl chloride resins commences with the monomer, vinyl chloride, which is a gas, shipped and stored under pressure to keep it in a liquid state bp —14°C, fp —160°C, density (20°C), 0.91. The monomer is produced by the reaction of hydrochloric acid with acetylene. This reaction can be carried out in eidier a liquid or gaseous state. In another technique, ethylene is reacted with chlorine to produce ethylene dichloride. This is then cataiytically dehydrohalogcnatcd to produce vinyl chloride. The byproduct is hydrogen chloride. A later process, oxychlorination, permits the regeneration of chlorine from HC1 for recycle to the process. 

Vinyl chloride can be synthesized by reaction of acetylene with hydrochloric acid over a mercuric chloride catalyst at 500 K and 5.0 atm total pressure. An undesirable side reaction is the subsequent reaction of vinyl chloride with HCl. These reactions are illustrated below. 

The method of making lewisite was suggested by the analogous method of mustard-gas manufacture used by the Allies. Thus, mustard is formed by the action of ethylene on sulfur monochloride, while lewisite is produced by action of acetylene on araeme trichloride in the pieaenct of aluminum trichloride acting as a catalyst. The dark brown viscid liquid a hich results from this latter reaction is decomposed by treatment with hydrochloric acid at O C. (32 F.), and an oil is obtained which < an be fractionated by distillation in vacuo into three chlor inyl derivatives of arsenic trichloride. These derivatives, which differ from each other only by the successive addition to the arsenic trichloride of one, two, or three molecules of acetylene, are as follows (see Chart Xlll) ... 

Stereospecific synthesis of 1,3-dienes. Corey et a .3 have described a new synthesis of 1,3-dienes based on the highly stereospecific cis addition of alkylcopper reagents to a, -acetylenic carbonyl compounds (3, 108). Thus the reaction of methyl 4-trimethyl-siloxy-2-nonynoate (l)4 in THF with divinylcopperlithium (1.25 eq) at —90° and then at — 78° affords the pure e(r adduct (2) in > 90% yield. Treatment of (2) with methanolic hydrochloric acid effects cleavage of the trimethylsilyl ether and lactonization to give (3). 

Derivation Action of chlorine on ethylene, with subsequent distillation with metallic catalyst also by reaction of acetylene and hydrochloric acid. Grade Technical, spectrophotometric. 

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